Voltage regulating system



Sept. 22, 1959 K. w. HESS 2,905,880 VOLTAGE REGULATING SYSTEM Filed NOV. 9. 1955 Input Voltage Tub: Currant Input Voltage Tub! CurI'QM J 16 17 Cyclic Tube -Swi\ching conduction Control control & Unit Unit il l wipw x AGENT United States Patent VOLTAGE REGULATING SYSTEM Karl Walter Hess, Eindhoven, Netherlands, assignor, by

mesne assignments, to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Application November 9, 1955, Serial No. 545,885

Claims priority, application Netherlands November 11, 1954 4 Claims. (Cl. 321-7) This invention concerns improved voltage regulating systems of the type utilizing polyphase transformers.

Voltage regulating systems are known which utilize a polyphase transformer for controlling the supply of A.C. loads by means of controlled electron discharge tubes of gas or vapor filled type; said tubes being connected to the primary side of said transformer. The tubes are so controlled that the frequency obtained at the secondary side of said transformer is lower than the frequency of the voltage applied to said primary side.

In these systems, the tubes usually operate at constant current values which are different for each tube. This causes the tubes to be loaded differently, so that the life of one tube is shorter than the life of another tube and several tubes operate with only a partial load. Furthermore, the primary windings of the transformer are loaded differently. Serious difiiculties are thus presented.

The disadvantages of known voltage regulating systems utilizing polyphase transformers are obviated by the system of the present invention, wherein the current control of the tubes is sequentially or cyclically shifted in such a manner that all the discharge tubes carry the same average load current. The cyclic control maybe effected in any known manner, such as by rotary contact switching means, relay control means, or electronic control means, operating in a predetermined sequence. Since all the electron discharge tubes carry the same average load current, the difficulties inherent in the known systems are avoided.

The principal object of this invention is the provision of a new and improved voltage regulating system of the type utilizing polyphase transformers.

Another object of this invention is the provision of a new and improved voltage regulating system which is simple in structure and inexpensive to operate.

A further object of this invention is the provision of a new and improved voltage regulating system having high operative efficiency.

These and other objects and features of the invention will be apparent from a consideration of the following detailed description taken in connection with the accompanying drawing, wherein:

Fig. 1 is a series of curves illustrating the input voltage and tube currents of a preferred embodiment of the voltage regulating system of the present invention, and

Fig. 2 is a preferred embodiment of the voltage regulating system of the present invention.

In Fig. 1 the curves 1, 2 and 3 represent the input voltages of the embodiment of the voltage regulating system shown in Fig. 2. Each of the curves 1, 2 and 3 represents a phase of said input voltage.

The curves 14, 15, 16, 17, 18 and 19 represent the currents carried by the tubes of the embodiment of the voltage regulating system shown in Fig. 2. The curves 14 and 17 represent the current in the tubes 8 and 9, the curves and 18 represent the current in the tubes 10 and 11, and the curves 16 and 19 represent the current in the tubes 12 and 13.

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The abscissa for all the curves is in time units.

The voltage regulating system shown in Fig. 2 comprises a polyphase transformer 4, which in the embodiment of Fig. 2, has three primary windings, 5, 6, and 7, and one secondary winding 14. The transformer 4 may be utilized for the welding of a workpiece at 15, if desired; said workpiece being connected across the secondary winding 14.

The primary winding 5 is connected in series with the anti-parallel connection of the controlled electron discharge tubes 8 and 9. The primary winding 6 is connected in series with the anti-parallel connection of the controlled electron discharge tubes 10 and 11. The primary winding 7 is connected in series with the antiparallel connection of the controlled electron discharge tubes 12 and 13.

Current control apparatus for controlling the current flow through the electron discharge tubes, may be of ay suitable type known in the art. Cyclic switching control, for controlling the operation of the electron discharge tubes may be of any suitable type known in the art. The electron discharge tubes 8, 9, 10, 11, 12 and 13 may be of gas or vapor filled type.

In operation, the voltage regulating system of Fig. 2 functions to make the tubes successively conductive in a predetermined sequence or cycle, in order to insure that all of said tubes carry the same average load current. The tubes may, for instance, be made conductive in the sequence 8, 10, 12, pause, 9, 11, 13. The current through each tube varies, as shown in Fig. l, by the curves 14, 15, 16, 17, 18 and 19. These curves indicate that the tubes 8 and 9 are least heavily loaded, the tubes 10 and 11 are loaded more heavily, and the tubes 12 and 13 are loaded most heavily. Thus the winding 5 is least heavily loaded, the winding 6 is more heavily loaded, and the winding 7 is most heavily loaded.

In accordance with the invention, after the tubes 8, 10 and 12 have been made conductive, they may be made conductive in the next cycle in the sequence 12, 8 and 10, and they may be made conductive in the cycle after that in the sequence 10, 12 and 8. The tubes 9, 11 and 13 also may be made conductive, they may be made conductive in the next cycle in the sequence 13, 9 and 11, and they may be made conductive in the cycle after that in the sequence 11, 13 and 9. As a result of these sequences, each tube and each primary winding is made to carry the same average load.

It is understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. An electrical circuit arrangement comprising input means for a polyphase alternating current supply, a plurality of electron discharge tubes each energized by a different phase of said current supply, a common output circuit for said discharge tubes, means for producing electrical conduction in said tubes in a given sequence and at given current values, and means for cyclically changing the conduction sequence of said tubes.

2. An electrical circuit arrangement comprising input means for a polyphase alternating current supply, a plurality of electron discharge tubes each energized by a different phase of said current supply, a common output circuit for said discharge tubes, means for producing electrical conduction in said tubes in a given sequence and at diflerent current values, and means for cyclically changing the conduction sequence of said tubes whereby the same average load current flows through said tubes.

3. An electrical circuit arrangement comprising input means for a polyphase alternating current supply, a plurality of electron discharge tubes each having a control tubes for producing electrical conductionin said tubes in a predetermined sequence and at difierent current values, means for cyclically changing the conduction sequence of said tubes, and means for deriving a common output voltage from said tubes comprising an output winding in inductive relation with the input windings of said system.

4. An electrical circuit arrangement comprising input imeans for a polyphase alternating current supply, a plurality of electron discharge tubes each having a control electrode, pairs of said tubes being connected in antiparallel connection, a series circuit arrangement con- -hected across each phase of said current supply comprising an input Winding connected in series with an anti-parallel connection of two of said tubes, means connected to the control electrodes of said tubes for produciug electrical conduction in said tubes in a predetermined 4 sequence and at different current values, said last-mentioned means comprising tube conduction control means for making each tube conducting and cyclic switching control means connected to the control electrode of each tube for coupling asid conduction control means to each tube in a desired predetermined sequence and means including said cyclic switching control means ,for cyclically changing the conduction sequence and the conduction current values of said tubes.

References Cited in the file of this patent UNITED STATES PATENTS 

